(Bloomberg) -- U.S. equities are rallying in a vacuum of money flows, which some strategists and traders say is a sign of losses to come.

In the week through Wednesday, $7.2 billion was pulled from U.S. stock funds, the ninth withdrawal in the last 10 weeks, according to data compiled by Bank of America Corp. and EPFR Global. At the same time, the S&P 500 Index has climbed 3.8 % from a low in March and the Nasdaq has jumped to a record.

While U.S. stocks have spent long stretches of the past six years rallying without the help of fresh mutual fund money, Bank of America and Exane BNP Paribas say the withdrawals show rising concern as the Federal Reserve weighs raising interest rates. Ian Richards of Exane says U.S. equities are especially vulnerable after going three years without a 10 % retreat.

“The outlook for U.S. markets over the course of the summer is pretty tricky,” said Richards, the head of equity strategy at Exane in London. “At some point, we’ll discount the implications of the first move in the U.S. rate cycle. The psychology around that is usually negative in equity trading.”

To be sure, a sudden reversal in the six-year rally that has driven U.S. equities to a record is not foreseen in the forecasts of strategists at 21 banks surveyed by Bloomberg. Their average estimate for where the S&P 500 will end 2015 is 2,237, more than 5.6 % higher than last week’s close.

STOCK VALUATIONS

The benchmark gauge for U.S. shares trades at about 18.6 times annual earnings, about 2 percentage points above its 10-year average, data compiled by Bloomberg show. While analysts predict profits will fall through the third quarter, they still see income rising in the full year -- and in 2016 and 2017.

Still, the S&P 500 is up 2.9 % since December after rallying an average of 18 % in each of the last three calendar years as economic figures are missing forecasts by the most in six years.

A fund tracking the S&P 500 has seen almost $38 billion pulled this year, according to data compiled by Bloomberg. In 2009, as investors withdrew a record $20 billion from the SPDR S&P 500 ETF Trust, the benchmark gauge jumped 23 %.

Speculators including hedge funds have boosted bearish bets. They’re net-short more than 48,000 S&P 500 contracts, near the most since June 2014, after being net-long 170,500 in January, according to data from the Commodity Futures Trading Commission.

Short interest on the biggest exchange-traded fund tracking the S&P 500 has almost tripled from the start of the year to 7.6 % of shares outstanding, data compiled by research firm Markit show. It reached its highest level since October this month.

“Big decoupling in recent weeks between U.S. equity flows and prices,” Bank of America strategists led by Michael Hartnett wrote in a note dated Thursday. “Correction risks will grow in the absence of fresh inflows in the coming weeks.”

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